Machine for making sheet metal pipe elbows



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Aug. 7, 1928.

F. BRUNE MACHINE FOR MAKING- ;SHEET METAL PIPE ELBOWS Filed March 28, 1925 8 Sheets-Sheet 2 @NN NNN MNM NMJ Aug. 7, 1928.

F. BRUNE MACHINE FOR MAKING SHEET METAL PIPE ELBOWS Aug. 7, 1928.

` F. BRUNE MACHINE FOR MAKING SHEET METAL PIPE ELBOWS *Q Q N Q 8 Smets-Sheet 4 ITU/veraf??? 5;:7 l a 2 v E d Aug. 7, 192s.

F. BRUNE MACHINE FOR MAKING SHEET METAL PIPE ELBOWS 8 Sheets-Sheet 5 Filed March 28, 1925 Aug. 7, 1928. 1,679,893

F. BRUNE MACHINE FOR MAKING SHEET METAL PIPE ELBOWS Filed March 28, 1925 48 Sheets-sheet e n o f 7 Y MM M5 xv n z. .Y 7 L h J N c Aug. 19m

Filed March 28, 1925 8 Sheets-Sheet '7 im Z 0. Z j N Aug. 7, 1928. 1,679,893

F. BRUNE Y KACHINE FOR MAKING SHEET METAL PIPE ELBOWS Filed March 28, 1925 8 Sheets-sheet 8 Egfezf x Patented Aug. 7, 1928.

UNITED STATES PATENT OFFICE.

MACHINE FOR MAKING SHEET-METAL-PIPE ELBOWS.

Application filed March n28, 1925. Seria1 No. 19,011.

My invention relates to the art of making elbows out of sections of sheet metal pipe by forming transverse crimps or folds in that side of the pipe which constitutes the inside or shorter curve of the elbow when completed. The invention is particularly useful for operation on pipe of relatively brittle metal, such as zinc, which has heretofore not been extensively used for elbows notwith* standing its superiority therefor by reason of its resistance to corrosion, because of its tendency to crack when sharply bent as in the machines heretofore in use. In my iml proved machine and process, the folds of the crimp are not crushed flat in the ini-tial operation of the machine thereon as in prior machines, but are first formed with slightly rounded, bends and thereafter flattened completely by a partially drawing or smoothing operation as will be understood from the following detailed description, thus avoiding the severe strains on the sheet metal of the tubes which are apt to crack them at the bend, especially when the tubes are of a less ductile metal, such as zinc. In my improved machine and process moreover it is possible and in fact desirable to operate on pipe sections, `t-he seams of lwhich are previously completely locked so that there is.s11bstan tially no relative movement between the interlocking edges. Thus, no further operation upon the elbows is necessary after they are formed in the machine, as required inthe case of the product of prior art machines. Furthermore, in the preferred form of the machine, the ipe is crimped on the portion of its peripliery opposite the seam, the crimps diminishing and. finally fading out at a short distance on the respectively opposite sides of the seam, so that the seam stiffens the pipe along the exposed outer side of the elbow where stiffening is particularly desirable. Other features and. advantages of my invention will appear from the following detailed description of the preferred form thereof. It is to be understood, however, that the specific disclosure is for the purpose of exemplification only and that the definition of the scope of the invention is reserved for the following claims in which I have endeavored to cover it as broadly as the prior art permits.

In the drawingsaccompanying and forming a part of the application, Figure 1 is a side elevation of a machine embodying my invention in its preferred form, the machine being .shown as partly broken away to show .features of the construction which would otherwise be hidden; Fig. 2 a plan View of the same; Fic'. 3 a vertical section on an enlarged scale of the forward end of the machine; Fig. 4 a similar view of the rear end of the machine and an elevation of certain elements of the front portion of the machine, intermediate parts being broken away; Fig. 5 a transverse vertical section on the plane of the line 5-5 of Fig. 3; Fig. 6 a horizontal section partly in elevation; Fig. 7 a rear end view of a. detail, parts being omitted for the sake of clearness; Fig. 8 a transverse vertical section on the plane of the line 8-8 of Fig. 9; Fig. 9 a longitudinal section of a portion of the man chine on the planes of the line 9-9 of Fig. 8; Fig. 10 a plan View partly in section of a detail; Fig. 1l a transverse vertical Section on the plane 11--11 of Fig. 3, parts being shown in elevation; Fig. 12 a similar view partly broken away and with the parts in a. different position which they occupy during the operation of the machine; Fig. 13 a front end view of the machine partly broken away to better show the construction; Fig. 14 a transverse vertical section on the plane of the line lll- 14.- of Fig. 3; Fig. l5 a longitudinal section on an enlarged scale of a portion of the machine showing the part-s ina position which they occupy during the making of a crimp; VF ig. 16 a similar View showing the parts however in a different position; and Fig. 17 an elevation of a. completed elbow.

I have shown my machine as designed for the making of elbows from corrugated scctions of pipe of the form now in common use for rain water conduits but, as will be manifest fron'i the following detailed description, with obvious changes it may be used for making elbows of pipe of other cross sectional form, such as cylindrical pipe. It has in common with earlier' machines for" the same purpose a fixed mandrel over the end of which the section of pipe from which the elbow is to be fcrmedis fed step by step, a. swinging mandrel or interior die, an expander operable between the fixed and swinging mandrels for forming the transverse bulges in the pipe which ultimately constitute the flattened crimps thereof, a clamp or gripping means surrounding the fr. ma.

fixed mandrel and adapted to grip the pipe sritlicieritly during the crimp forming opera.- t-ion and to cooperate in the latter, butto permit the pipe to be pushed therethrough intermediate the crimping operations and a clamp cooperating' with the swinging mandrel to flatten and complete the crimp and properly hold the pipe aga-inst the swinging mandrel. during the loi-mation el the lollowing crimp.

'lhc fixed mandrel lis oit a length to receive the pipe lengths to be formed into elbows and is formed in two sections, the rear section El() being` supported at its rear end as at 3l in a bracket 32 on the trame or stand 33 of the machine, see Fig. i). The :forward section 34 of the mandrel threaded on the reduced lorward end 35 of the rear section. Exteriorly the mandrel is termed tlnfoughout its operative length in accordance with the crosssectional shape ot tlieielbow to be termed; in the present example ot the invention l have shown the mandrel as corrugated as this machine is designed for the manufacture of elbows from corrugated pipe, such as shown in Fig. li'. The forward or end section 34 o'lf the mandrel houses and guides the erpanders lor forming the hulges in the pipe, and these ekpanders are operate-d by a plunger' 5o extending through and `reciprocable in the mandrel as will presently appear.

Referring now more particularly to Figs. 3, 8 and T, it will be seen that the eXpanders for bulging or expanding the metal et the tube to form the crimps ot the elbow, comprises a series of knuckles 38 which are arranged just beyond the end edge of the lined mandrel and are so mounted as to be capable oi' swinging in and out in planes radial to the mandrel. The knuckles are formed on the ends of arms or bars S9 which have a limited longitudinal and swinging movement in radial slots or recesses 40, 'formed in the end orl the mandrel. rlhe longitudinal movement oit' the knuckle bars is limited by the engagement ot toes 4l on the respective bars .in slots 42 in the wall ot the mandrel. rlhe inner edges o'l the rear pob tions of the knuckle bars are curved to rock upon a ring 43 which is sleeved upo-n the plunger 3G after the bars 39 have been inserted into their positions with their toes .in the slots as above described. The knuckles are swung in and out the required distance to form the bulge and retreat within the circumference ot the mandrel by links 44, the inner ends of which are reeiprocated or swung longitudinally ol the mandrel by the plunger 362 ln the preierred construction shown, the end oit the ijilunger is reduced as at 45 to receive a collar 4G which is rabbeted or cut away for a portion ot its periphery, corre spending in location to the knuckles, as at nordsee 47. 'lhe cutaway portion ot the collar 46 is occupied by sector-shaped blocks 48 to which the respective links 44 are pivoted as at 49, see Figs. 8 and 9. The sector-shaped blocks are respectively formed or provided with pins 50 which extend into holes suitably located in the collar 46 to receive them and the end ol the reduced portion of the plunger is threaded as at 52 to receive a nut 53. jitter the sector blocks have been put in place the nut is screwed on the end ot the plunger and holds them in` position. Obviously with the construction just described, when the plunger is reciprocated. the bulge forming knuckles are alternatelyspread to the position shown in Fig. 9 and retracted to the position shown Iin Fig. 3. rlhe means for reciprocating the plunger will be presently described..

As will be readily understood Yfrom Fig. 8, the expanding or lungo-formingknuckles are distributed about so much ot the eircmnllei.1n ence in which the vcrimp is to be termed in the pipe section, there being, however, a substantial are in which no such knuckles are provided. This arc corresponds to the outside portion of the elbow, see Fig. 17, that is to say, the portion ot maximum radius, in which also the seam of the pipe is located, so that the latter does not interfere in any way withthe formation of the crimp. In the construction shown the crimping.mechanism is so arranged that the pipe lengths may be inserted with their seai'ns underneath. Obviously the knuckles are shaped according to the cross-sectional shape of the pipe section. ln the machine illustrated which is adapted :tor the making of elbows 'from corrugated pipe, not only the mandrel is corrugated, as before explained, but the knuckles are so formed as to extend into and engage the internal concavities or channels of the pipe without unduly distorting them except to iorm the transverse bulge.

A swinging mandrel or head 54 of substantially the diameter oit the main or stationary mandrel and concentric therewith is hinged to the latter as best shown in Fig. 9, so as to normally form a continuation of the stationary mandrel beyond the plane of the lmlge-lorming knuckles. In the particular machine chosen tor illustration et the inven tion aV bore 56 is formed in the metal 57 o the end of the stationary mandrel and a similar bore 58 in the metal ofthe swinging man`- drel, the two bores being in line. Plugs 59, 60 are inserted in the respective bores and pivoted or knuckled together at G1. Screws 62, 63 hold the plugs in their respective sockets.

It will be noted that the adjacent ends of the fixed and swinging mandrels respectively are inclined so that `when they are in normal coaxial positions as shown in Fig. V9 the space between ysaid mandrels corresponds in gerif eral form and dimensions with the bulge to be formed in the pipe sections and provides room for the expanding knuckles to operate between the adjacent ed ges ot the respective mandrels. The bulge which is to form the crimp in the pipe is formed by spreading or expanding the knuckles when the lixed and swinging mandrels are coaxial as shown in Fig. 9. After the bulge has been formed and the expanding knuckles retracted, the swinging mandrel is swung over until its edge is close to that of the ixed n'iandrel and substantially parallel thereto to fold or flatten the bulge into a crimp as will be presently explained.

During each crimp-'forming operation the pipe section is firmly clamped to the respective mandrels. For this purpose, I provide what I shall term a `fixed clamp, inasmuch as it has no bodily movement, in connection with the fixed mandreland a swinging clamp pivoted coaxially and movable with the swinging mandrel. Both of these clamps are supported from a transverse web or bracket mounted upon the iframe ot the machine and formed With an opening 68 through which the fixed mandrel projects. The construction and operation of the tixed clamp may best be explained in connection with Figs. 3, 1l and 19.. Swinging jaws 66, 67 are pivoted to the web 65 immediately above and on opposite sides of the center of the opening 68. By reference to Fig. 3, it will be seen that the opening 68 is of slightly larger diameter than the exterior of the mandrel to permit a. pipe section on the latter' to extend therethrough, and that the opening flares to the rear. The bearing faces 69, 70 of the respective jaws conform to the` shape of the mandrel and of the pipe section on which the machine is designed to operate and are nearly senii-cir cumferential, meeting4 together in a diae metric plane below the mandrel. They are formed at their free ends with lugs 7l, 72, respectively, the outer or remote edges 7 3, 7 t of which are approximately parallel to their meeting edges. The lower edges 75, 76 of the lugs are chamfered or inclined for a purpose which will presently appear. A locking' slide plate 77 slides in Vertical guides 78, 79 secured to the face of the web 65, the upper face of the slide plate being provided with a notch 80 of a width slightly greater than the combined width of the lugs 71, 72 when the clam is closed. The slide plate is adapted and esigned to be raised to the position shown in Fig. 11, in which the lugs enter the notch and the clamping jaws are firmly locked in `closed position. On opposite sides of the notch the upper edge of the slide plate inclines `upwardly in opposite directions, thus making a flaring throat. As the jaws are spread when the slide plate is lowered, when it is moved upwardly the cammed upper edge ot the slide plate forces the lugs toward the central position and into the locking notch. A wire spring 8l is interposed between the lugs on the respective cla-mp jaws, the ends of the spring entering sockets therein, so that the spring yieldably forces the jaws into the open posit-ion shown in Fig. l2 when the locking slide plate is in lower position. But when the slide plate is raised as shown in Fig. ll it forces the jaws together previously described. The slide plate may be raised by means of a handlevcr 84 pivoted to guide 78 at 85 and having'a slot 86 in which Works a pin 87 upon said slide. u

A gap intervenes between the clamping faces of the jaws at the upper ends thereof even when said jaws are closed, but this gap is filled by a vertically reciprocating clamping member 88 which descends to the position shown in Fig. ll when the jaws are closed and ascends to the position shown in Fig. l2 when the jaws are open. The jaw '88 is formed on its rear tace with a spline edges 92, 93 thereoiiare inclined so that this portion oit the clamp member is wedgeshaped to closely the gap between the upper ends of the swinging' jaws when the latter are closed. The lower portion of the clamp member 88 just described is connected by a vertical web 95 extending' between the upper ends of the pivoted jaws with a cross tree 96 which extends over the ends of the pivoted jaws. By an inspection et Figs. 1l and l2 it will be seen that the jaws 66, 67 are provided adjacent their pivots with cam faces 97, 98, respectively, which operate upon the rounded ends et the cross tree 96 when the jaws are opened to raise the sliding jaw 88 as shown in F ig. l2. When the swinging jaws are closed, however, the vertically sliding aw descends and the swinging aws bear thereon at 99, 100, respectively, to firmly press the ysliding jaw against the pipe on the mandrel. The pipe lengths to be formed into elbows are thrust over or on to the mandrel to secure the Vlocation ot the first crimp a proper distance from the end oi' the pipe lengths. The jaws are then closed and locked in closed position by raising the handle St. The fixed clamp thereafter holds the pipe section firmly in position on the fixed mandrel, but the pressure is not such as to prevent the step by step movement of t-he pipe forward through the clamp, as hereinafter described, without opening the latter which maintained closed from the time the pipe section is inserted until the crimping thorcoil' is completed.

rl`he construction and operation of the llt) swin,f 'ingr clamp which cooperates with the swinging mandrel will now be described, reterence being had particularly to Figs. 1, 3, 19, 13 and 14. The swinging jaws ot the swinging clamps are mounted upon a supporting:v plate 110 which is pivoted concentrically with the swinging mandrel by means oi truimions 11.1, 112 journaled in brackets 113, 114 which are bolted to the same cross plate (S5, heretofore described, which supports the lixed clamp. lt will be noted that the trimi'iiims mentioned are toi-med on or 'ecured to rear 'ardly extending; lugs 115, 116 on lthe plate 119 so that the plane o1 the latter is somewhat in advance ot' the trunnions. lflate 110 is lf'orn'ied with an opening for the passage o1 the pipe section. coaxial with the opening' in the stationary supporting plate and with the mandrels. The jaws 113, 119 ot the swingingI clamps are hung on bolts 120, 121, respectively, cross each other at 122, embrace the swinging` mandrel 54 and are provided with operatii'ip; means, to be presently desrribed, at their :lree ends. lo. order that the jaws may cross each other at 122 and that at the same time the main bodies thereof may be opposite each other, the upper ends ol the respective jaws are cut away shown at 125, (see full lines in Figs. 1 and 14 and dotted lines in Fig'. 13), and suitable washers 126, 127 are applied to the bolts 120, 121 respectively, to secure the proper position ot' the jaws thereon. The inner or adjacent edges of the jaws are shaped to conform to the pipe to be operated upon, and in the present instance are corrugated. They are cut away and overlap to some extent where they bear on top of the pipe as clearly shown in dotted and l'ull lines in 13 and 14 and malte contact with the pipe Atrein the point ot overlap to some distance below the center thereot as shown in Fig. 13. 1 provide supplementary clamping.;l jaws 'tor engaging;- the lower portion of the pipe. These jaws or wings 130, 131 are pivoted to a pin or bolt 132 which has a slight vertical movement in a slot 132L in supporting` plate 110, see dotted lines Fig. 14. The jaws or wings extend on opposite sides ot and beneath the swinging mandrel and thepipe thereon and when the jaws 118, 119 are opened tall outwardly by gravity, the pivot bolt 132 dropping` to the bottom of the slot 13211. llihen the jaws 113, 119 close they engage the wings and raise and close the latter by engaging them with the cam surilaces 133, 134 which bear upon the outside edges of the respective supplemental swinging,` aws. The supplemental jaws are torn'ied or provided with sections 135 and 13G, respectively, o12 a guide for the seam ji/ ot the pipe and, of course are correspondinglv notched to allow for the feed. 1n order to limit the movement ot the jaws they are provided respectively. with pins 137, 138

ner/sees playingn respectively in slots 139, 140 formed in the supportingV plate 110.

At their respective free ends the aws 118, 119 are provided with rollers: 141, 142 journaled thereon for cooperation with the mounted on the trame beneath the jaws.

lllithin the boxing are a pair of independently actuated slides 144, 145 mounted one above the other and movable longitudinally of the machine. The lower slide 145 is provided with a transverse groove or channel 147 into which the rollers 141, 142 extend, the length oit the channel beingl suiiicient to provide ample movement- :tor the opening of the jaws. llVhen the slide is reciprocated the jaws and the supporting plate to which they are attached are tilted on the trunnions 111, 112. The second or upper slide is provided with an obtuse V-shaped slot 148, the apex et the V being toward the rear, through the respective branches ot' which vslot the rollers 141, 142 extend. Obviously when the two slides move relatively to each other or when one moves while the other is stationary, the jaws are opened or closed.

'lhe section ot pipe being` crimped to form the elbow is ted 'forward stepbystep after its insertion in the machine by means of a collar 15() which slidesupon the mandrel. 'l`he collar is recessed or its bore enlarged at 151 and. receives a band 152 in the recess, the interior ot which is corrugated or otherwise -lormed to correspond to the exterior of the mandrel but is of suiiiciently larger size to permit the insertion of the end of the pipo section to be operated upon betweenk said band and the mandrel.

l will now describe the means for giving the part-s thus far described their operative motions. Referring to 1, 2 and 4, it will be seen that the machine is lprovided at its rear end with a transverse operating shaft 160, shown as driven'by a belt pulley 161, and provided with a bevel pinion 162. Said pinion meshes with a bevel gear 163 keyed to a shaft 164 which is mounted coaXially with the mandrel in brackets 165 and 32 on the main `frame ot the machine. Said shaft has keyed thereto the various cams 'tor operating1 the moving members of the machine. At its rearmost end is the cam 168 for swinging` the swinging' mandrel. It is l.frrooved at 169 to receive the roller 170 of a longitudinallyV ,moving slide 171. To the upper end ot the slide at 172 is secured a rod 173 which extends through an axial borek 17 4 in the shaft 134 and a similar bore 17 6 in the plunger 3G. At its forward end said rod is provided with a flanged block 1.77 which extends loosely through a vertical slot 178 in the swinging mandrel. The flanges 179,

180 of the block are obtuse angled in their respective adjacent faces, as best shown in Fig. 9, and engage the opposite faces of the swinging mandrel to permit a pivotal movement of the latter as the rod is reciprocated. Thus the mandrel `may be swung from the normal position of Figs. 39 and 16 to the inclined position of Figs. Li and 15.

The cam cylinder 185 on said shaft controls both the opening and closing of the swinging clamp and the tilting thereof. As best seen in F 2 and 4, it is provided with a cam groove 186 which receives a roller 187 carried by a slidebar 188 mounted for longitudinal reciprocation beneath said cam cylinder. As seen in Fig. 1, the forward end of said bar is dropped and receives the rear end ofia rod 189, the forward end of which is connected to the slide 145 by which the swinging clamp and its supporting plate are controlled in their movements about the trunnions 111-112.

The other cam groove 190 in said cylinder receives the roller 191 on the slide bar 192, the forward end of which is likewise dropped and connected by a rod 193 with the upper slide 144 which is formed with the V- slot, as above described, and controls the opening and closing of the jaws of the swinging clam Immediately in advance of the cam. cylinder 185 is a smaller cam cylinder 195 which operates to advance the collar 150 by which the. pipe sections being converted into elbows are given their step by step movement intermediate crimping operations. Cylinder 195 is formed with a cam groove 196 in which runs a roller 197 mounted on a stud on the reciprocating bar 198. The latter is guided at 199 in the bracket 32 and extends loosely through a guide 200 upon the collar 150. The slide 198 is formed on its under edge with ratchet teeth or notches 201 which are engaged by a pawl 202 which is pivoted to said collar at 203, the pawl being held against the ratcheted face of the bar 198 by a spring 203. The collar is fed forward one notch or tooth with each reeiprocation of said bar. The rearward movement of the collar is prevented by a pawl 204 which is pivoted to the collar at 205 and pressed downwardly by the same spring 203a which operates on pawl 202, and engages ratchet teeth 206 formed in the upper face of the mandrel.

A cam cylinder 207 of yet smaller diameter than cylinder 195 is carried on the front end of the shaft 164 and is journaled in the bracket 32, as best shown in Fig. 3. The cam cylinder or sleeve 207 controls the reciprocation of the plunger 36 by means of which the bulge forming knuckles are spread and retracted. `For this purpose, the said sleeve is formed with a cam groove 208 in which runs a roller 209 mounted on the rear under .face of a slide block 210. Said block is guided in the bracket 32 (see Figs. 3 and 5) and at the forward end of its under face is formed or provided with a lug or pin 211 which extends into a hole 212 formed in the rear end of said plunger. Gbviously, as the shaft and the cam cylinder 207 rotate, the plunger is reciprocated operating the cxpanding knuckles as above described.

Automatic means is provided for stopping the machine and opening the iixed clamp when the elbow being formed is completed. For this purpose, a lever comprising the arms 215, 216 and .shaft 217 is mounted on the side of the machine, as best seen in Fig. 2, the rear arm 215 controlling a clutch between shaft 160 and pulley 161. This clutch may be of any known or suitable construction adapted to be operated by a swinging arm, such as 215 and it is, therefore, not considered necessary to describe it. The other arm 216 of the lever extends to or past the front of the machine being guided and limited in its swinging movement by the guide bar 218. At its forward end as at 219, it extends beneath the hand lever 84 and so long as the arm 216 is elevated, in the position shown in Fig. 11, which is the po sition it occupies during the operation of the machine, it keeps the fixed clamp closed. Ti/Vhen it drops, however, it permits the lixed clamp to open and likewise the dropping of the arm 216 of the lever accompanied as it is by the raising of the arm 215 throws out the clutch controlled by the latter thus bringing the machine to rest. Arm 216 is maintained in its upper or raised position by a latch 220 which slides crosswise of the machine, see F ig. 2. The inner end of the latch has a pin 221 which engages in a slot 222 in the end of the bell crank lever 223. The bell crank lever is pivoted at 224 and its shorter arm 225 extends into the path of a linger 226 depending from the collar 150. The contact of said arm 225 with the finger may be adj usted by means of the screw 227. WVhen the last crimp has been formed in the particular elbow being made, the finger 226 engages the bell crank lever causing the latter to` withdraw the latch 220 from beneath the arm 216 and the latter thereupon drops permitting the .iixed clamp to open and opening the clutch by which the machine is driven.

The movement of the parts of the machine has been described in connection with their structure, but may be briefly summarized as follow-s: After each elbow is completed, the machine comes to rest withthe bulge forming knuckles in the retracted position, the swinging mandrel co-axial with the fixed mandrel,l the swinging clamp in vertical position and both clamps open, all as shown in Fig. 3. The pipe advancing collar is in its forward position having just tripped the stop mechanism of the machine. The pipe advancing collar, preferably, is first set back to such a position that when the next pipe section to be operated upon is put on the fixed mandrel and piopeily engaged with the collar, it will be properly located with reference to the crimp forming means so that the lirst crimp will be pioperly placed. The location of the collar may be effected by `aiiiching together the pawls 202, 204. A pipe length is then passed through both clamps and over the mandrels, with its seam underneath and guided in the seam guides 185, 13G and thrust rearwardly until in proper engagen'ient with the advancing collar 150. ily raising the lever arm i216, the lined clamp is closed about the pipe on the fixed mandrel and the clutch shifted to set the machine in operation. rlhe arrangement and relation of the cams is such that the slide 1411i is first moved te close the jaws of the swinging clamp. The spreading ofthe crimp forming knuckles then takes place, due to the forward movement of the plunger 36, after which the knuckles are immediately withdrawn by the action of the cam. lhe swinging mandrel and swinging clamp are then swung rearwardly together by the operating means above described to fold the previously formed bulge rearwardly, as seen iu liig. 15. rlhe slide 11h/l next moves rearwardly to release the jaws of the swinging clamp which, together with the swinging mandrel is moved to the upright co-axial position, shown in Fig. 3. The pipe section is then moved forward through the fixed clamp and over the fixed mandrel to the position shown in Fig. 1G in which the just formed crimp is within the plane of the swinging clamp. rll'hc jaws of the latter then close upon the folded metal of the crimp and press it flat. rlliis completes the cycle of operation for the formation of the first crimp and the further operation of the machine again spreads the bulge forming knuckles and the other steps of the previously described operation are repeated. yiifter the predetermined number of crimps have been formed in the pipe section, the advance of the pipe feeding collar operates the bell crank lever to release the clutch shifting lever and the machine returns to rest.

By reference to Figs. 11, 12, 15 and 1G, it will be seen that the members of the fixed clamp are so shaped about their forward edges as at 231 as to form a tapering forwardly projecting nozzle, the opening of which is on an incline. lt is also called to attention that the rear edge of the opening formed by the jaws of the swinging clamp is flared as at 232 so that when, upon the completion of the bulge, the swinging clamp is drawn rearwardly into the position shown in Fig. 15 the nozzle of the hired clamp, along the upper portion of its edge, projects slightly within the rounded edge of the opening of the swinging clamp. [is seen in Fig.

inverses 15, the mating of these parts is not such, however, as to squeeze the edge of the fold or crimp, but the latter remains slightly rounded. 'l'he joint action of the two clamps leaves the crimp standing out from the pipe at a slight angle as shown in Fig. 15, but `when the crimp in this state is advanced and the jaws of the swinging clamp close thereon,"

the fold of the crimp is flattened down sniocthly, as shown in Fig. 1G. By thus avoiding crushing the metal flat at the line of foldduring the opeiation of collapsing l the bulge to forni the crimp or tuck and thereafter flattening out the tuck or crimp by the action of the swinging clamp cooperating with the swinging mandrel, the tendency to crack the metal along the line or fold is greatly diminished, enabling the Ina! chine to be used for forming elbows of relatively brittle material, such as sheet zinc. l claim:

1. ln armacliine of the class described, a

ing therewith, the pivots of said jaws beingv spaced a substantial distance apart and said jaws crossing each other intermediate their respective pivots and the mandrel and each adapted to bear on the pipe on the mandrel for approximately a quarter of its circumference and means for clamping the `pipe to the mandrel for approximately lthe other half of the circumference.

3. In a machine of the class described, a

mandrel, a pair of clamping jaws cooperat.

ing therewith, the pivots of said jawsbeing spaced a substantial distance apart 4and saidy jaws crossingV each other intermediate their respective pivots and the mandrel and each adapted tobear on the pipe on themandrel for approximately a quarter of its circumference and means for clamping the pipe to the mandrel for approximately the other` half of the circumference, of the pipe, said means being operated by the opening and closing of said jaws. i

l. In a device of the class described, a mandrel, a main pair of clamping jaws pivoted at a distance from each other and crossing each other intermediatetheir respective pivots and the mandrel and adaptedv to jointly operate on `substantially a semicircumference of a pipe on the mandrel, and a pair of supplemental pivoted jaws engaged by the main jaws and clamping kthe pipe substantially throughout the other portion of its circumference. l

5. ln a machine of the class described,a

Slt

i 'no iso mandrel, a main pair of clamping jaws adapted to engage a pipe on the mandrel on the side thereof adjacent the pivots of said jaws, a pair of supplemental swinging jaws adapted to engage the pipe on the other side thereof, said supplemental jaws engaged and operated by the main jaws and means :tor opening and closing the main jaws.

6. A machine as described in claim 5 in which the means for opening and closing the main jaws engages the latter at their free ends.

7. In a machine of the class described, a mandrel, a pair of pivoted jaws cooperating therewith and extending at their free ends on the opposite side of the mandrel from their pivots and a cam plate engaging the free ends of the jaws for opening and closing the latter.

8. In a machine of the class described, a mandrel, a pair of pivoted clamping jaws, a cam plate having a V-shaped slot through the respective arms of which the free ends of the jaws extend, and means for reciprocating the cam plate.

9. In a machine of the class described, a swinging mandrel, a pair of clamping jaws cooperating therewith, a pivoted supporting plate 0n which said jaws are pivoted, the

jaws being extended beyond the mandrel and means engaging the free ends of the jaws for swinging them and their supporting plate.

10. In a machine of the class described, a swinging mandrel, a pair of clamping jaws cooperating therewith, a pivoted plate on which said supporting jaws are pivoted, a plate having a cam slot through which said jaws extend, means for reciprocating said cam plate, a second slide plate into which said jaws extend and means for reciprocating said slide plate to swing the jaws and their support.

l1. In a machine of the class described, a swinging mandrel, a supporting plate piv- Oted to swing with said mandrel, a pair of clamping jaws pivoted to said plate and cooperating with the mandrel, a pair of independently operated slide plates both engaging the jaws, one of said slide plates having a cani slot for opening and closing the jaws and the other slide plate having a transverse groove into which said jaws extend, and mechanism for operating the second said plate to swing the jaws and their support.

12. In a machine for :forming pipe elbows from sheet metal pipe, aixed mandrel adapted to receive a length of pipe from which an elbow is t0 be formed, a clamp surrounding the mandrel and having a lip ex tending partially around the inner periphery oi the clamp, said lip having a narrow rounded edge, a second mandrel normally concentric with the lixed mandrel and adapt? ed to swing to an inclined position, a clamp surrounding the second mandrel and clamp, the second said clamp being rounded opposite the narrow lip on the iirst mentioned clamp so as to engage the rounded edge only of the latter, means for forming a bulge in the pipe intermediate said mandrels and clamps when the latter are in normal position and means for swinging the last mentioned mandrel and clamp toward the first mentioned mandrel and clamp to collapse a previously formed bulge in the pipe.

FRIEDERIOH BRUNE. 

